Chemistry - October 2007

2007-10-23 20:28:09 · 5 answers · asked by Anonymous

1) CCl4
2) HCl
3) H2CO
4) BF4 -
5) NH3

2007-10-23 20:20:18 · 7 answers · asked by Anonymous

Equal masses of oxygen (O2) and fluorine (F2) are placed in separate flasks at the same volume and temperature. Which of the following statements is true? Circle the correct answer.

a) Do both flasks contain same number of molecules?

b) Are the molecules of oxygen moving faster than fluorine?

c) Is the pressure in the oxygen flask is higher than the pressure in the fluorine flask?

d) Are more molecules are present in the fluorine flask?

2007-10-23 20:03:38 · 3 answers · asked by Hellos 1

Calculate each of the following quantities.
(a) volume of 14.7 M sulfuric acid that must be added to water to prepare 2.00 L of a 0.271 M solution

(b) molarity of the solution obtained by diluting 75.7 mL of 0.231 M ammonium chloride to 0.250 L

(c) volume of water added to 0.150 L of 0.0252 M sodium hydroxide to obtain a 0.0100 M solution (assume the volumes are additive at these low concentrations)

(d) mass of calcium nitrate in each milliliter of a solution prepared by diluting 56.5 mL of 0.726 M calcium nitrate to a final volume of 0.100 L

2007-10-23 19:48:14 · 3 answers · asked by Ruby Winter 2

list some of them

we have to spray it to repel public away when they disturb whilst arranging a concert...

2007-10-23 19:43:29 · 12 answers · asked by Shehzad Roy 1

The structures of caffeine and theobromine are very similar. What characteristic absorption bands would you expect to find in the IR that would not be present in caffeine?

2007-10-23 17:32:31 · 0 answers · asked by Anonymous

A 100.-mL sample of solution contains 10.0 mmol of Ca2+ ion. How many mmol of solid Na2SO4 must be added in order to cause precipitaton of 99.9% of the calcium as CaSO4? The Ksp of CaSO4 is 6.1 x 10^-5. Assume the volume remains constant.

Please help, I don't know the steps to do these kinds of problems.

2007-10-23 16:34:55 · 1 answers · asked by Anonymous

Organic solid such as naphthalene and 1, 4-dichlorobenzene are widely used as mothballs b/c they are toxic to insects ans sublime at a slow rate at atmospheric pressure. Other organic solids such as urea and lactic acid do not have any appreciable vapor pressure under ambient conditions. Explain this behavior in terms of the structure of the molecules.

2007-10-23 16:18:19 · 1 answers · asked by Anonymous

2007-10-23 16:10:07 · 8 answers · asked by sportsfanatic1089 2

2007-10-23 16:08:20 · 4 answers · asked by Anonymous

2007-10-23 15:39:41 · 12 answers · asked by Anonymous

Consider 50 mL of a solution that is 0.25 M in both H2PO41- and HPO42-.

What is the pH of the solution?

2007-10-23 15:35:37 · 1 answers · asked by Anonymous

A chemistry question: How do I convert a solution of x% v/v (by volume) aqueous solution into y% v/v?

To make my question more clear, say I have a 50% v/v aqueous ammonium hydroxide solution. How would I determine how much water to add to it to change it to 2.5% v/v aqueous solution?

I do not want an answer to the ammonium hydroxide question. I want a process to follow to figure out this type of problem. Thanks.

2007-10-23 15:11:20 · 2 answers · asked by akfortysheep 1

2007-10-23 15:01:32 · 3 answers · asked by Anonymous

2007-10-23 14:46:08 · 7 answers · asked by harlm7 2

Like in 2Na + Br2 ==> 2NaBr , which is oxidized and which is reduced?

2007-10-23 14:40:08 · 10 answers · asked by chrissymoo7 3

We need to calculate our school's carbon footprint.

2007-10-23 14:36:12 · 6 answers · asked by Jesse B 2

2007-10-23 14:15:10 · 5 answers · asked by 22 4

besides water??

2007-10-23 14:11:32 · 7 answers · asked by katheryn n 2

I have this equation:
2Mg+O2 (heat) > 2MgO

Is this BOTH a combination and a combustion reaction? Thanks!

2007-10-23 13:35:13 · 1 answers · asked by Tank Cat 1

1.Translate the following chemical equation into a sentence.
CH4+2O2--->CO2+2H2O

2.Perform the following calculations andwrite the answer with the correct number of significant figures.
a. 12.65m times 42.1m
b. 3.7g/1.083cm*3

2007-10-23 13:29:43 · 1 answers · asked by Anonymous

need this answer as sooon as possible like...by tomorrow

2007-10-23 13:13:09 · 5 answers · asked by jonathan r 1

Consider the following data.

N2(g) + O2(g) 2 NO(g) H = +180.7 kJ
2 NO(g) + O2(g) 2 NO2(g) H = -113.1 kJ
2 N2O(g) 2 N2(g) + O2(g) H = -163.2 kJ

Use Hess's law to calculate H for the reaction below.

N2(g) + 2 O2(g) 2 NO2(g)
H = ____ kJ

2007-10-23 13:04:00 · 2 answers · asked by Circuiteer 1

2007-10-23 12:23:40 · 2 answers · asked by Anonymous

which of these hydrates ( CuSO4, CdCl2, CaCl2) will have a vapor pressure of water:

A) Greater than the partial vapor pressure of water in the atmosphere at room temperature? Explain.

B) Less than the partial vapor pressure of water in the atmosphere at room temperature? Explain.

2007-10-23 11:56:28 · 1 answers · asked by NEEDs MATH HELP!! 1

which of these hydrates ( CuSO4, CdCl2, CaCl2) will have a vapor pressure of water:

A) Greater than the partial vapor pressure of water in the atmosphere at room temperature? Explain.

B) Less than the partial vapor pressure of water in the atmosphere at room temperature? Explain.

2007-10-23 11:49:15 · 1 answers · asked by NEEDs MATH HELP!! 1

2007-10-23 11:47:14 · 3 answers · asked by Anonymous

I need 0.5mol/L of the following HCl (lemon juice), NaOH(Drain Clearner), Acetic acid(vinegar) and sodium bicarbonate(baking soda). The problem is I don't know what the concentration of HCl is in lemon juice. Same thing for the other three items. How would I do this?

2007-10-23 10:10:43 · 2 answers · asked by llllllllllllll 2

I found a website that said that Ca(OH)2 is completely ionized but not soluble in water... how does that work? If it's not soluble then how is it a strong base?

2007-10-23 10:07:53 · 1 answers · asked by AC 1

2007-10-23 09:07:17 · 7 answers · asked by Anonymous